> On Fri, Sep 30, 2016 at 01:13:02PM -0500, Steve Wise wrote: > > > Hum, so I expect the patch to break things. Specifically if you change > > > the process credentials after opening verbs. However just forking() > > > shouldn't cause a problem. Can you confirm there is nothing that > > > changes uid,gid, etc during the fork? > > > > I'll debug this further, but this is running as root, so that sort of stuff > > shouldn't be changing. > > Based on some emails I've got I think there is a 'thing' with > credentials in Linux where something copies the creds struct but > (perhaps?) does not change it. > > Linus designed the test to be a pointer compare, so if anything does a > copy-but-no-modify then it will break the test unnecessarily. If I > understand everything properly :| > > If you can add any more information I'm sure people will appreciate > it. > > > Fork() is actually not supported by this preload library, but we were > > getting by, I guess, with netserver because it fork()s before it allocates > > the UDP socket that then gets accelerated by the preload lib. However, I'm > > thinking that librdacm is getting invoked and is opening contexts to all the > > verbs devices before the fork() and thus after it, this new "safe" check it > > biting me. > > Hmm, sounds plausible. Same deal with rdmacm, it has to close/open the > verbs device. Defering doing anything until first needed would also be > a reasonable strategy. I think it does. But perhaps my offload lib is actually the culprit. It goes and walks all the interfaces and builds a database of available devices that can support this user mode UDP stack. I'll post more as I identify the root cause. Steve. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
